Circuit interrupting device



June 7, 1949. KOHL CIRCUIT INTERRUPTING DEVICE 4 Sheets--Sheet 1 Filed Sept. 8, 1944 I .l 2 3 2 w w 1 2 mlwlm M Q r Q: N l 5 H022 224/ xv a l H I 0 1 A... 4 8 H fa N r v 0 f 60 6 2 3 T u a 7 W K [at INVENTOR. E/eraraF/(o/fl.

June 7, 1949. E. F. KOHL 2,472,332

CIRCUIT INTERRUPTING' DEVICE.

Filed Sept. 8, 1944 4 Sheets-Sheet 2 Fi i WMW

June 7, 1949. E. F. KOHL 2,472,332

CIRCUIT INTERRUPTING DEVICE Filed Sept. 8, 1944 l 4 Sheets-Sheet I5 IN VEN TOR.

June 7, 1949. E. F. KOHL 2,472,332

' TING DEVICE Filed Sept. 8, 1944 l 4 Sheets-Sheet 4 INVE R.

fverardfl' a Z. BY

Patented June 7, 1949 UNITED STATES ATENT ()FFICE CIRCUIT INTERRUPTING DEVICE Everard 1F. Kohl, Lakewood, Ohio Application September 8, 1944, Serial No. 553,243

17 Claims. 1

My invention relates to circuit interrupting devices and more particularly to a device of this type which is sensitive in interrupting and establishing an electrical circuit when a shaft with which the device is associated is rotated above or below a predetermined speed and constitutes an improvement of the apparatus described and claimed in my copending application, Ser. No. 443,205, filed on May 16, 1942, now Pat. #2410,- 663, November 5, 1946.

An object of my invention is to provide an improved circuit interrupting device in which a circuit may be quickly interrupted when the device is rotated above a predetermined speed and quickly reestablished when the rotative speed of the device falls below the predetermined speed.

Another object of my invention is to provide an improved circuit interrupting device in which a circuit may be quickly interrupted when the device is rotated above a predetermined speed and quickly reestablished when the device falls below the predetermined speed, including adjustable means for regulating the speed at which the circuit is interrupted and established.

My invention will be better understood by reference to the accompanying drawings in which:

Fig. 1 is a cross sectional view of my improved circuit interrupting device installed in a motor with the motor casing shown partly in section and partly in elevation;

Figs. 2 and 3 are cross sectional views on the lines 22 and 33, respectively, of Fig. 1;

Fig. 4 is a View taken on a plane through substantially the line 44 of Fig. 1 looking in the direction of the arrows and showing parts in section and parts in elevation;

Fig. 5 is a cross sectional view of another form of my improved circuit interrupting device installed in a motor with a fragmentary portion of the motor shown in section;

Fig. 6 is a detail view as seen from a plane taken through the lines 6-6 of Fig. 5, looking in the direction of the arrows;

Fig. 7 is a plan view of the detail shown in Fig. 6;

Fig. 8 is an end view of the circuit interrupting device shown in Fig. 5 taken on planes passing through lines 8-8 of Fig. 5, looking in the direction of the arrows;

Fig. 9 is a cross sectional view on the line 9-9 ofFig.5;

, Fig. 10 is a longitudinal cross sectional view of another form of my improved circuit interrupting device;

Figs. 11 and 12 are cross sectional views on substantially the lines H-Il and I2i2 of Fig. 10 as viewed in the direction of the arrows; and

Fig. 13 is an end view of the circuit interrupting device shown in Fig. 10.

Broadly stated, my improved circuit interrupting device comprises a casing containing an electrically conductive liquid which establishes an electric circuit when the device is at rest or is being rotated at a predetermined speed and which interrupts the circuit when the device is rotated above the predetermined speed. It may, for instance, be associated with a motor to control its speed, in which case it acts as a governor, or it may be utilized to establish a circuit to an auxii ary device, such as a solenoid, the coil of an electromagnet, an electrical switch, or to another motor when a driven shaft with which it is associated is rotated below or at a predetermined speed and to interrupt the circuit to the auxiliary device when the driven shaft is rotated above the predetermined speed. It may also be utilized in combination with a driving and a driven shaft to maintain the rotative speed of the driven shaft at a substantially constant speed at any desired speed below that of the driving shaft.

One form of my improved invention is shown in Figs. 1 to 4 of the drawings in which my improved circuit interrupting device is associated with and is adapted to be connected in the load circuit of a motor to control the motor speed. As illustrated in Figs. 1 to 4 of the drawings, my improved circuit interrupting device is arranged within a casing l which may be attached to the frame of a motor 2 by any suitable means, such as bolts 3, and comprises a housing 4 formed of a conductive metal provided with a cover 5 which may be welded or otherwise secured thereto and a hub E which may be affixed to the motor shaft 1 by any suitable means. As illustrated, the motor shaft is provided with a sleeve 8, a ring of insulating material 9 is interposed between the sleeve 8 and the hub 5, and a set screw [0 spaced by an aperture from hub 6 is threaded through insulating ring and sleeve 8 into the motor shaft.

The housing is shaped to provide a contact chamber i! and a communicating or displacement chamber l2 of greater peripheral extent than the contact chamber in which is arranged a ring 33 formed of a resilient material, such as rubber, the outer periphery of which normally engages the inner periphery of a flange H extending inwardly from the cover. The housing contains an electrically conductive liquid, such 3 as mercury, which provides an electrical circuit between an annular slip ring l connected to the housing by suitable means, such as bolts i6, and an annular slip ring I! spaced inwardly from slip ring I5 which is insulated from housing t by a channeled ring l8.

To provide the circuit between slip rings it; and I! when the housing is at rest or is being rotated at low speed, an insulating plate It having an inwardly extending substantially annular flange 29 at its outer periphery is provided in contact chamber H and a flat ring 2! formed of a conductive material is arranged adjacent the periphery of insulating plate It with the outer edge abutting flange 20 and is connected to slip ring I! by suitable conductive means, such as bolts 22. As shown, each bolt is passed through slip ring l", insulating ring I8, an insulating washer 23, insulating plate l9, ring 2 I and is secured to ring Ed by any suitable means, such as a nut 24, and when housing It is at rest, the conductive liquid settles at the bottom of the casing as shown in Fig. l and a circuit is established from slip ring i5 through casing l to the conductive liquid and from thence through ring 2| and bolts 22 to slip ring I1.

When housing 4 is rotated at suificient speed to centrifugally throw the mercury outwardly, the mercury seeps in to the displacement chamber between flange M and resilient ring it and partially immerses ring I3 and when housing 5 is rotated at a predetermined speed, the mercury buoys resilient ring f3 inwardly to form a space for the liquid at the outer periphery of the displacement chamber. The inward buoyant force of the mercury in displacement chamber 12 depends upon the depth of immersion of ring if.- in the mercury and the rotative speed of the housing and increases as the square of the speed of the mercury which rotates with the housing. It is. therefore apparent that at a predetermined speed a sufiicient amount of the mercury in the contact chamber will be thrown into the displacement chamber to interrupt the circuit between slip rings l5 and I1.

It is the purpose of the present invention, however, to provide an improved circuit interrupting device in which the circuit is quickly interrupted when the motor is rotated above a predetermined speed and quickly reestablished when the motor falls below the predetermined speed. For this purpose, a substantially rectangular notch is pro.- vided in flange 2D to form a recess 25 and a contact 26 having one end fastened to ring 2| by nut 24 has its opposite end extending into recess 25 with its central portion biased to the right as shown in Fig. l, and a sufficient amount of mercury is provided in housing 4 so that when the motor is being rotated at the desired speed. the resilient ring l3 shall be immersed in the men. cury to such a depth that there will be sunicient mercury in recess 25 to engage contact 25' and an electrical circuit will be established between slip ring [5, housing 5,, contact 26, and bolt 22. to slip ring [1. Since the amount of mercury in recess 25 is comparatively small, it will be apparent that a slight increase of the rotative speed of housing 4 above its predetermined speed will increase the buoyant force of the mercury Sufi.- ciently to quickly provide a space in the comparatively large displacement chamber I 2 to receive sufficient mercury from recess 25 to interrupt the circuit.

The inward buoyant force of the mercury upon resilient ring l3 also decreases as the square of the speed of the housing when the rotative speed of housing t slows down in which case resilient ring l3 tends to assume the position it occupied when the housing was being rotated at the predetermined speed and a portion of the mercury is forced out of the displacement chamber into recess 25 to reestablish the circuit and since the space for the mercury in the displacement chamber is so much largerthan recess 25, it will be apparent that only a slight outward movement of ring l3 will .be required to displace suiilcient mercury to fill recess 25 to a sufiicient extent to quickly reestablish the circuit.

Means are also provided to regulate the speed at which the circuit is interrupted. For this purpose, cover 5 is provided with an inwardly extending bore 2? to receive a plunger 28 formed oi. a molded insulating material and a screw 29 threaded in casing I engages plunger 28 and increases the depth of immersion of spring 26 in recess 25. When screw 28 is threaded in the opposite direction spring 26 is again flexed outwardly and the upper portion of spring 26 returns to its normal position. Plunger 28 is slidahis in bore 2? and consequently when plunger 28 is removed, the mercury may be introduced in the housing through hub 21.

The circuit interrupting device may be connected in the load circuit of the motor by any desirable means. As illustrated current from line L1 is electrically connected to a carbon brush 30 which is resiliently maintained in engagement with slip ring 8'5 and is conducted from slip ring ill by a carbon brush to a lead 32 which is con nected to the power line of the motor and back to the source of supply.

Another modification of my invention is shown in Figs. 5 to 9 or the drawings. As illustrated, the circuit interrupting device shown in this modification comprises a housing 33 including a cover 3d provided with an inwardly extending flange 35 engaging the inner periphery of the housing and an outwardly extending hub 36 provided with a slip ring 31,. The housing 35 may be connected to the shaft 38 of a motor in any desired manner. As illustrated the free end of shaft as extends through, a central opening in the housing and is provided with a sleeve 39 afixed thereto by any suitable means, such as a set screw 48, and the housing is afiixed to but insulated from the sleeve by an insulating ring ll abutting a shoulder on the sleeve and an insulating ring d2 held in place by a nut 43 threaded on the end of the sleeve.

The housing is shaped to form a comparatively large segment or displacement chamber 44 which communicates with a narrow contact chamber of less peripheral extent than the segment charrber. As illustrated the segment or displacement chamber includes a plurality of segments Mi which are normally maintained in engagement with flange 35 by any suitable means, such as springs ll, the opposite ends of each of which are embedded in. apertures formed in adjacent segments. Segments 45 may be formed of any su table material which is capable of being buoyed inwardly by the mercury, such as molded fal'arie. wood, hollow metal, or the like. As. illustrated, they are formed of molded calcium aluminosilicate.

The housing contains a suitable conductive liquid. such as mercury, and when the housing is at rest, means are provided to, establish an. electrical circuit between slip ring 3'! and. a slip ring which is seated in the recess of the enlarged portion 50 of a sleeve the inner portion of which sleeve is peened or otherwise affixed to a conductive plate 52 arranged within the contact chamber.

Slip ring 31 is insulated from slip ring 49 by the hub 53 of an insulating plate 54 arranged within the contact chamber and by an insulating sleeve 55 having a flange 56 arranged between the slip rings and consequently when the casing is at rest, an electrical circuit is established from a suitable source of electrical energy L1 to a carbon brush 5?, sleeve 5!, conductive plate 52 to the conductive liquid within the housing and from the liquid through flange 35 and cover 34 to slip ring 31 from whence it may be conducted through a carbon brush 58 to the load circuit of the motor and from the motor back to the source of supply.

When housing 33 is rotated at a predetermined speed, however, the mercury is thrown outwardly forming an annulus of liquid between flange 55 and the segments 46, thus interrupting the circuit between conductive plate 52 and the mercury.

It is the purpose of the present invention, however, to provide means for quickly interrupting the circuit when the housing is rotated above a predetermined speed and to quickly reestablish the circuit when the housing falls below the desired speed and this is particularly true when the circuit interrupting device is inserted in the load circuit of the motor and it is desired to maintain the motor at a predetermined substantially constant speed.

For this purpose, insulating plate '54 is provided with a substantially annular flange 59 which has a rectangular notch formed therein to provide a recess 50 and the portion of flange 54 below the recess is provided with a narrow rectangular slot to receive the free end of a conductive spring 5|, the other end of the spring being connected to the plate 52 by suitable means, such as a screw 62.

In accordance with my invention, when the housing is being rotated at the desired speed, the mercury is thrown outwardly by centrifugal force and a portion of the mercury seeps in between flange 35 and segmental blocks 46 and immerses the segments to a depth in which a portion of the mercury is in recess 60. When housing 33 is rotated above the predetermined speed, however, the inward. buoyant force of the mercury forces segments 46 inwardly forming a space between flange 35 and segmental blocks 46 to receive sinflcient mercury from recess 60 to quickly interrupt the circuit. The quick interruption of the circuit is due to the fact that as the speed of the housing increases beyond the predetermined speed, the inward buoyant force of the mercury increases as the square of the speed and also because only a slight inward movement of the segments is required to provide a space between flange 35 and segmental blocks 46 to receive from recess 60 the comparatively small amount of mercury which it is necessary to remove from that recess to interrupt the circuit.

Assuming that the circuit interrupting device is connected in the load line of the motor, it will be apparent that when the circuit to the motor is interrupted, the speed of the motor will slow down and upon decrease of the speed of the housing, the inwardly buoyant force of the mercury will decrease as the square of the speed. Spring 51 will then force segments 46 outwardly toward the inner periphery of the casing, causing sufficient mercury to flow into recess 60 to reestablish the circuit. The springs which are placed under tension when the segments are forced inwardly also expand quickly to restore the segments to the position corresponding to the desired speed. It will therefore be apparent that the motor may be operated at a substantially constant speed.

Means are also provided to regulate the speed at which the circuit is interrupted. For this purpose, spring contact 6| is provided with an inwardly bowed central portion which is adapted to be engaged by a plunger 63 extending through sleeve 5! and the other end of plunger 63 is adapted to be engaged by a screw 64 threaded to one end of the casing. Upon threading screw 54 inwardly, it will be apparent that the end of spring 5i extending in recess 50 will be lowered, thus decreasing the speed of the housing at which the circuit is interrupted and when screw 64 is threaded in the opposite direction, the position of the end of the spring extending into recess 63 will be raised and it will require a higher rotative speed of the housing to interrupt the circuit. The mercury may be inserted in the housing through sleeve 5| when plunger 63 is removed.

In the modifications shown in Figs. 1 to 4 and in the modification shown in Figs. 5 to 9, it will of course be apparent that instead of connecting the circuit interrupting device in the load line of the motor, it may be utilized to energize or deenergize other apparatus, such as a solenoid, the coil of an electromagnet, or may be utilized to regulate the speed of another motor when the speed of the motor to which the circuit interrupting device is attached rises above or falls below a predetermined speed.

Another modification of my improved governor or circuit interrupting device is shown in Figs. 10 to 13 of the drawings which includes a housing which terminates at one end in a hub 9| secured to a shaft 66 by suitable means, such as a set screw 92, and is provided at the opposite end with a cover 93 which is welded or otherwise secured to the housing, such as by bolts 94, and which is provided with a central threaded opening to receive shaft 66, a sleeve 95 formed of a suitable insulating material which is slidable on shaft 66, and an adjusting screw 95 which is threaded into the central opening of the cover and which is engageable with a shoulder 91 on sleeve 95.

The governor contains an electrically conductive liquid which also has a comparatively high buoyant power, such as mercury, and its parts are constructed and arranged to provide an electrical circuit between shaft 66 and a slip ring 98 when shaft 56 is at rest or is being rotated at or below the desired speed and to interrupt the circuit when the shaft is rotated above the desired speed. For this purpose, the housing 90 is provided with a segment or displacement chamber extending between cover 93 and an annular shoulder 99 to receive a plurality of segmental blocks I00 which are normally maintained in engagement with the inner periphery of housing 90 by means of springs I01, each provided with flanges I02 and 03 at its opposite ends which fit into longitudinally extending grooves in the locks. Blocks 100 may be formed of any suitable material which is capable of being buoyed inwardly by the mercury during rotation of the governor, such as wood, molded fabric, hollow metal, or the like. As illustrated, they are formed of a molded material composed essentially of calcium aluminosilicate and while only two blocks are shown, a greater number may of course be provided. While the blocks I substantially fill the segment chamber which extends between cover 93 and the shoulder 99, they are spaced sufficiently apart so that they may be buoyed radially inwardly by the mercury to form a space for the mercury between housing 90 and the outer periphery of the blocks and there is sufiicient clearance between the blocks and the shoulder to form an annulus between the inner periphery of housing 90 and blocks I00 when the governor is rotated at a predetermined speed.

To provide contact between slip ring 98 and the mercury within the housing when the governor is at rest or is being rotated at or below the desired speed, a contact chamber I04 is arranged inwardly of shoulder 99 which is of less peripheral extent than the segment chamber and in which is arranged a circular plate I05 formed of a molded insulating material, such as calcium aluminosilicate, which is provided with a substantially annular flange I06, and a fiat annular ring I0! formed of a conductive metal is arranged within flange I06 which may be electrically connected to slip ring 03 in any desired manner. As illustrated, slip ring 98 is insulated from housing 90 by a ring I08 having an annular flange I09 and a plurality of spaced insulating sleeves H0 are arranged in housing 90 adjacent flange I09 to receive bolts 1 I I, the head of each of which bolts engages ring I01 and the shank of each of which passes through an aperture in plate I05, one of the sleeves IE0, and through aligned apertures in flange I09 and a flange IIZ on slip ring I08, and is peened or otherwise secured to flange l 52.

As illustrated in the drawings, current from a suitable source of electrical energy L1 is grounded through shaft 66 to casing 90 and a stationary brush I it slides upon slip ring 98 during rotation of shaft 66. A conductor L2 leading back to the source of electrical energy is connected to brush IIG. When casing 90 is at rest or is being rotated at low speed, a circuit is established from conductor L1 to L2 through shaft 66, casing 90, and from the mercury through ring I 01, bolts II, slip ring 08 and brush II6 to line L2. mined speed, however, the mercury in casing 90 will be thrown outwardly by centrifugal force and will seep between blocks I 00 and the annular shoulder 99 on the housing to form an annulus of liquid between housing 90 and the segmental blocks and when governor 0! is rotated at a predetermined speed, the mercury will buoy blocks I00 inwardly against the force of springs IOI, thereby forming a space for the mercury and interrupting the circuit between shaft 66 and slip ring 98.

As illustrated in the drawings, blocks H10 are held against the inner periphery of housing 96 by springs IOI. They are also thrown outwardly by centrifugal force but at a critical speed are buoyed inwardly by the mercury against their own centrifugal force and the force of springs I 0|. The inward buoyant force of the mercury depends upon the composition of blocks I00, the tension of springs IOI which tend to hold the blocks against the inner periphery of the housing, the depth of immersion of the blocks in the mercury and the rotative speed of the governor.

The outward force of springs IOI upon the blocks, however, is a constant factor and consequently When shaft 66 is rotated above a predeterwhen blocks I00 are formed of a predetermined material, such as calcium aluminosilicate, the inward buoyant force of the mercury upon the blocks will be determined by the depth of immersion of the blocks in the mercury and the rotative speed of the governor. The inward buoyant force of the mercury, however, increases as the square of the speed and consequently at a certain predetermined speed, blocks I00 will be buoyed radially inwardly providing a space for the mercury between the inner periphery of housing and blocks I00, thus interrupting the circuit.

It is the aim of the present invention, however, to provide a segment chamber of comparatively large size and to arrange the parts so that the circuit will be interrupted and established by the final flow of only a small amount of mercury between the contact chamber and the segment chamber so that the circuit will be quickly interrupted when shaft 65 rises above a predetermined speed and will be quickly reestablished when shaft 66 falls below the predetermined speed. For this purpose, a substantially rectangular opening is formed in flange l 86 to provide a recess I I I and a narrow rectangular slot I I'Ia is cut in the portion of the flange below the opening to receive mercury from the contact chamber.

From the drawings, it will be apparent that during the rotation of the governor the mercury will be thrown outwardly into recess I I1 and when the mercury is in this recess to a sufficient depth, means are provided fcrestablishing a circuit between shaft 66 and slip ring 08. For this purpose, a resilient spring M8 is provided having a central opening to receive shaft 66 and arcuateshaped sides which engage a shoulder H9 on sleeve Spring H8 is also provided with a narrow rectangular arm I28 which extends forwardly and outwardly and the free end of which extends through slot Illa into recess II! and bears upon the portion of flange I00 adjacent slot Illa, and an oppositely extending narrow projection I2I which is fastened to annular ring Illl' by one of the bolts III. When mercury is in recess II! to a suflicient depth, it will be apparent that an electrical circuit is established from shaft 66 through housing 00 to the mercury in recess ill and from thence to the spring and through bolt II I to slip ring 98.

Means are also provided to adjust the position of arm I20 in recess II! so that the speed of shaft lit at which the circuit is interrupted may be regulated. For this purpose, spring H8 is biased to exert a pressure on shoulder II9 of sleeve 65 and the opening in the spring is elongated to permit upward and downward movement of arm I20. As illustrated in the drawings, the position of the end of arm I20 in recess II! is regulated by adjusting screw 96 which when threaded inwardly engages a shoulder 91 of sleeve 95 and moves arm I26 upwardly so that it will require a higher speed of shaft 66 to interrupt the circuit than when the parts are in the position shown in Fig. 12. On the other hand when screw 3!? is threaded outwardly, spring 56 will force sleeve 95 outwardly to or beyond the position shown in Fig. 12' and arm E20 will be moved inwardly to decrease the speed required to interrupt the circuit. The mercury may be introduced into and removed from the housing through apertures in cover 03 which are normally closed by threaded plugs I22.

According to my invention, the amount of mercury introduced in the housing is just suflicient so that when the governor is being rotated at the desired speed, the mercury in recess II! will be in contact with spring H8. When the speed of shaft 68 rises, however, blocks it) will be buoyed further inwardly and a sufficient quantity of the comparatively small amount of mercury in recess M! will be quickly displaced to interrupt the circuit when shaft 86 slows down, the buoyant force of the mercury upon blocks I00 decreases and blocks lilii are forced outwardly by springs Ill! and their own centrifugal force, and mercury flows from the space between cover 90 and blocks l8 into recess H1. Since the segment chamber is much larger than recess Ill, it is apparent that it will require only a slight outward movement of blocks 00 to again cause mercury to flow into recess H! and consequently any slight decrease in the speed of shaft 66 below the desired speed wi l quickly reestablish the circuit. The rotative speed of shaft 65 at which the circuit is interrupted and established may of course be varied by adjusting screw 96.

What I claim is:

1. Apparatus of the class described comprising a housing containing a conductive liquid,

said hOllSiIlg being shaped to provide a narrow contact chamber and a segment chamber havin a greater width and peripheral extent than the contact chamber. a contact arranged in the contact chamber which is in electrical circuit with i;

said liquid when the casing is at rest, and a plurality of segmental blocks arranged in the segment chamber which are displaceable by the centrifuga1l developed buoyant force of the liquid to provide a space in the second chamber for 2. Apparatus of the class described compris ing a housing containing a conductive liquid, said housing being shaped to provide a contact chamber and a second communicating chamber of greater peripheral extent than the contact chamber, means providing a comparatively small recess at the periphery of the contact chamber, a contact having a portion arranged in said recess to establish an electrical circuit between said contact and said liquid when said housing is being rotated at suflicient speed to centrifugally throw the liquid to the periphery of the contact chamber, and means in the second chamber displaceable by the centrifugally-developed buoyant force of the liquid to provide a space in the second chamber for receiving at least a suiiicient amount of liquid from said recess to interrupt the circuit between said contact and said liquid when said casing is moved about one of its axes above a predetermined speed.

3. Apparatus of the class described comprising a housing containing an electrically conductive liquid, said housing being shaped to provide a contact chamber and a second communicating chamber of greater peripheral extent than the contact chamber, means providing a small re cess at the outer periphery of the contact chamber and a contact having a portion arranged in said recess to provide an electric circuit between said liquid and said contact when the conductive liquid is in said recess, said liquid being cen trifugally displaceable to form an annulus in second chamber and being present in an amount sufficient to provide liquid in said recess when the housing is rotated at a predetermined speed, and means in the second chamber movable radially liquid, said housing being shaped to provide a contact chamber and a segment chamber of greater peripheral extent than the contact chamher, a plurality of segmental blocks arranged in said segment chamber, spring means for maintaining said segments in engagement with the inner periphery of the segment chamber when said casing is at rest, means providing a small recess at the outer periphery of the contact chamber, and a contact having a portion arranged in said recess to provide an electrical circuit between said liquid and said contact when the conductive liquid is in said recess, said liquid being centrifugally displaceable to form an annulus in the segment chamber and being present in an amount suificient to provide liquid in said recess when the housing is rotated at a predetermined speed and said blocks being movable' radially inwardly by the centrifugally-developed buoyant force of the liquid to provide a space in said segment chamber for receiving a sufficient amount of liquid from said recess when the housing is rotated above the predetermined speed to quickly interrupt said circuit and said blocks being movable outwardly against the inward buoyant force of said liquid by said spring means to return sufiicient liquid to said recess to quickly reestablish the circuit when the housing falls below the predetermined speed.

5. Apparatus of the class described comprising a rotatable housing containing an electrically conductive liquid, said housing being shaped to provide a contact chamber and a second communicating chamber of greater peripheral extent than the contact chamber, a contact arranged in the contact chamber which is in electrical circuit with said liquid When said casing is being rotated at a predetermined speed, means displaceable by the centrifugally-developed buoyant force of the liquid to provide a space in the second chamber for said liquid when the casing is moved about one of its axes above a predetermined speed to thereby interrupt the circuit between the contact and said liquid, and said contact being movable to interrupt said circuit at various speeds of said housing.

6. Apparatus of the class described comprising a rotatable housing containing an electrically conductive liquid, said housing being shaped to provide a contact chamber and a second communicating chamber of greater peripheral extent than the contact chamber, a contact arranged in the contact chamber which is in contact with said liquid when said casing is being rotated at a predetermined speed, and means arranged in the second chamber which is displaceable by the centrifugally-developed buoyant force of the liquid to provide a space in the second chamber for said liquid when the housing is moved about one of its axes above a predetermined speed to thereby interrupt the circuit between the contact and said liquid, and said contact being movable away from and toward the periphery of said contact chamber to interrupt said circuit at various speeds of said housing.

'7. Apparatus of the class described comprising a rotatable housing containing an electrically conductive liquid, said housing being shaped to provide a contact chamber and a second communicating chamber of greater peripheral extent than the contact chamber, means providing a small recess at the outer periphery of the contact chamber to receive a portion of the conductive liquid when said housing is rotating at a predetermined speed, a contact having a portion arranged in said recess which is in circuit with said liquid when the housing is rotated at the predetermined speed, displaceable means arranged within the second chamber to form a space to receive sufiicient liquid from said recess when the housing is rotated above the predetermined speed to interrupt said circuit, and means whereby said contact may be moved in said recess to interrupt said circuit at various speeds of said housing.

8. Apparatus of the class described comprising a rotatable housing containing an electrically conductive liquid, said housing being shaped to provide a contact chamber and a second communicating chamber of greater peripheral extent than the contact chamber, electrically conductive means arranged within said contact chamber which is in electrical circuit with said liquid when said housing is at rest, means arranged in said contact chamber for-providing a small recess at the outer periphery of said contact chamber, a contact having a portion arranged within said recess to provide an electrical circuit between said contact and the liquid when said housing is rotated at sufiicient speed to centrifugally throw the liquid to the outer periphery of said housing, and means within the second chamber displaceable by the centrifugally-developed buoyant force of the liquid to form a space in the second chamber to receive a sufficient amount of the liquid from said recess to quickly interrupt the circuit between the contact and the liquid when said housing is rotated above a predetermined speed.

9. Apparatus of the class described comprising a housing containing an electrically conductive liquid, said housing being shaped to provide a contact chamber and a second communicating chamber of greater peripheral extent than said contact chamber, means providing a recess at the periphery of said contact chamber, a contact having a portion extending into said recess to form an electrical circuit with said liquid when said housing is being rotated at a predetermined speed, and resilient means arranged in said second chamber which conforms to the inner periphery of the second chamber when said housing is at rest, said resilient means being displaceable by the centrifugally-developed buoyant force of said liquid to form a space in the second chamber to receive a sufilcient amount of the liquid from said recess to interrupt said circuit when the housing is rotated above the predetermined speed, and having sufficient resiliency to force sufiicient liquid back into said recess to reestablish said circuit when the housing again rotates at its predetermined speed.

10. Apparatus of the class described comprising a rotatable housing containing an electrically conductive liquid, said housing being shaped to provide a contact chamber and a second communicating chamber of greater peripheral extent than said contact chamber, means providing a recess at the periphery of said contact chamber, a shaft, an insulating sleeve slidable on said shaft,

a contact having a portion engaging said sleeve and a portion extending into said recess which is in electrical circuit with said liquid when the housing is rotated at a predetermined speed, and means arranged in the second chamber which is displaceable radially inwardly by the centrifugally-developed buoyant force of said liquid to provide a space for receiving sufiicient liquid from said recess in the second chamber when said housing is rotated above its predetermined speed to interrupt said circuit, and means accessible from outside of said housing for moving said sleeve to adjust the position of said contact in said recess to interrupt said circuit at various speeds of said housing.

11.. Apparatus of the class described comprising a rotatable housing containing an electrically conductive liquid, a contact arranged in said housing for forming an electrical circuit with said liquid when the housing is being rotated at a predetermined speed and being spaced from said liquid to interrupt the circuit when the housing is rotated above the predetermined speed, and means arranged outside of said housing for adjusting the position of said contact to interrupt said circuit at various speeds of said housing.

12. Apparatus of the class described comprising a rotatable housing containing an electrically conductive liquid, a contact having a portion arranged adjacent the periphery of said housing and forming an electrical circuit with said liquid when the housing is being rotated at a predetermined speed and being spaced from said liquid to interrupt said circuit when the housing is rotated above the predetermined speed, and means arranged outside of said housing for adjusting the position of said contact relative to the inner periphery of said housing for interrupting said circuit at Various speeds of said housing.

13. Apparatus of the class described comprising a housing containin an electrically conductive liquid, said housing being shaped to provide a narrow contact chamber and a second communicating chamber or greater width and peripheral extent than the contact chamber, a contact arranged in the contact chamber which is in electrical circuit with said liquid when the casing is at rest, and means in the second chamber which engages the inner periphery of the housing forming the second chamber over a comparatively large area when the casing is at rest, said means being displaceable by the centrifugally-developed buoyant force of the liquid to provide a space in the second chammr for said liquid when said casing is moved about one of its axes at a predetermined speed to thereby interrupt the circuit between the contact and said liquid.

14. Apparatus of the class described comprising a rotatable housing containing an electrically conductive liquid, said housing being shaped to provide a contact chamber and a second communicating chamber of greater peripheral extent than the contact chamber, means for rotating said housing, insulating means arranged in the contact chamber having an inwardly extending peripheral flange engaging the housing wall forming the inner periphery of the contact chamber, electrically conductive means arranged in the contact chamber with its outer periphery engaging said flange, said electrically conductive means being in electrical circuit with said liquid when said housing is at rest and said flange being provided with a recess which communicates with both of said chambers, a contact having a free end arranged within said recess and a portion electrically connected to said conductive means to provide an electrical circuit between said contact and the liquid when the housing is rotated at sufficient speed to centrifugally throw all the liquid from the contact chamber into the second communicating chamber with the exception of liquid which remains in said recess, and means within the second chamber displaceable by the centrifugally-developed buoyant force of the liquid to form a space in the second chamber to receive suflicient liquid from said recess to quickly interrupt the circuit between the contact and the liquid when the housing is rotated above the predetermined speed.

15. Apparatus oi the class described comprising a rotatable housing containing an electrically conductive liquid, said housing being shaped to provide a contact chamber and a second communicating chamber of reater peripheral extent than the contact chamber, means for rotating said housing, insulating means arranged in said housing having an inwardly extending peripheral flange engaging the inner periphery of that portion of the housing which forms the contact chamber, electrically conductive means arranged in the contact chamber with its outer periphery engaging said flange and said electrically conductive means being in electrical circuit with said liquid when said housing is at rest, and said flange being provided with a recess adjacent the periphery of said contact chamber which communicates with the contact chamber and the second communicating chamber, a contact having a free end arranged within said recess, an intermediate portion, and a portion connected to said electrically conductive means to provide an electrical circuit between said contact and said liquid when the housing is rotated at sufficient speed to centrifugally throw all the liquid from the contact chamber into the second communicating chamber with the exception of liquid which remains in said recess, means within the second chamber displaceable by the centrifugally-developed buoyant force of the liquid to form a space in the second chamber to receive suflicient liquid from said recess to quickly interrupt the circuit between the contact and the liquid when the housing is rotated above the predetermined speed, and means whereby said contact may be engaged intermediate its ends to regulate the position of its free end in said recess.

16. Apparatus of the class described comprising a rotatable housing containing an electrically conductive liquid, said housing being shaped to provide a contact chamber and a second communieating chamber of greater peripheral extent than the contact chamber, means for rotating said housing, insulating means arranged in the contact chamber having an inwardly extending peripheral flange engaging the housing wall forming the inner periphery of the contact chamber, electrically conductive means arranged in the contact chamber with its outer periphery engaging said flange, said electrically conductive means being in electrical circuit with said liquid when said casin is at rest and said flange being provided with a recess which communicates with the contact chamber and the second communicating chamber, a resilient contact having a free end arranged within said recess and a portion electrically connected to said conductive means to provide an electrical circuit between said contact and the liquid when the housing is rotated at sufiicient speed to centriiugally throw all the liquid from the contact chamber into the second communicatin chamber with the exception of liquid which remains in said recess, means within the second chamber displaceable by the centrifugally-developed buoyant force of the liquid to form a space in the second chamber to receive sufiicient liquid from said recess to quickly interrupt the circuit between the contact and the liquid when the housing is rotated above a predetermined speed, and means whereby force may be applied to said contact intermediate its ends to bow the central portion of said contact away from alignment with its ends to thereby decrease the extent to which the free end of said contact is extended into said recess.

17. Apparatus of the class described comprising a rotatable housing containing an electrically conductive liquid, said housing being shaped to provide a contact chamber and a second communicating chamber of greater peripheral extent than the contact chamber, means for rotating said housing, insulating means arranged in the contact chamber havin an inwardly extending peripheral flange engaging the housing wall forming the inner periphery of the contact chamber, electrically conductive means arranged in the contact chamber with its outer periphery engaging said flange, said electrically conductive means being in electrical circuit with said liquid when said casing is at rest and said flange being provided with a recess which communicates with the contact chamber and the second communicating chamber, a resilient contact having a free end arranged within said recess, a bowed central portion, and a portion electrically connected to said conductive means to provide an electrical circuit between said contact and the liquid when the housing is rotated at sufficient speed to centrifugally throw all the liquid from the contact chamber into the second communicating chamber with the exception of liquid which remains in said recess, means within the second chamber displaceable by the centrifugally-developed buoyant force of the liquid to form a space in the second chamber to receive sufficient liquid cfrom said recess to quickly interrupt the circuit between the contact and the liquid when the housing is rotated above a predetermined speed, and means whereby the central bowed portion of said contact may be engaged and moved to force the bowed portion of the contact toward alignment with its ends to thereby increase the extent of the free end of said contact in said recess.

EVERARD F. KOHL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,498,113 Olds June 17, 1924 1,917,581 Gillen July 11, 1933 2,081,604 Schaum May 25, 1937 2,302,125 Howell Nov. 17, 1942 2,366,631 Lambert Jan. 2, 1945 

